In a large skillet, heat oil. Add onion and saute for 2 minutes. Add ground turkey and saute for about 5 minutes, or until browned. Drain fat. Add chili powder, cumin, garlic powder, salt, kidney beans, and chopped tomatoes. Simmer for 15 minutes.
While chili is simmering, cook pasta as directed on package. Drain.
Top spaghetti with chili, and sprinkle with shredded low-fat cheddar cheese.